The literal translation of ‘lives’ in this narration is ‘blood’. The Prophet ﷺ also mentions here that ‘people trust them with their lives and wealth’ indicating that it is for all people and not just in regards to other Muslims. Additionally, notice these are two very big trusts which indicate the level of excellence a believer should uphold and manifest—which can only come from some excellent quality they have inside. As a person develops their faith, the characteristic of trustworthiness should begin to flow naturally as a result of that person’s heightened awareness of God ﷻ: that He fully encompasses them in His knowledge and that they will have to answer to Him about their actions. This causes them to focus on doing what pleases God ﷻ and avoid what displeases Him. Furthermore, one can only really develop their faith by taking the path of seeking sacred Islamic knowledge where they learn under qualified scholars who have studied the tradition—under a line of other scholars, who go all the way back to God’s Messenger—and live it, learning who God ﷻ and His Messenger ﷺ really are, what they really taught, and then to act upon that knowledge. To claim to have complete belief yet lack trustworthy qualities is make a very deficient claim—and God knows best.